Updated 8:17 pm, Friday, September 22, 2017

Sen. Bernie Sanders, I-Vt., during a nurses convention rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sanders promoted his Medicare for All 2017 plan.

Sen. Bernie Sanders, I-Vt., during a nurses convention rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sanders promoted his Medicare for All 2017 plan.

Photo: Santiago Mejia, The Chronicle

U.S. Senator Bernie Sanders speaks to the overflow crowd section at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA.

U.S. Senator Bernie Sanders speaks to the overflow crowd section at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA.

Photo: Paul Kuroda, Special To The Chronicle

Richard Compton and Sandy Harris purchase buttons from John Jefferson as they wait to see U.S. Senator Bernie Sanders speaks at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA

Richard Compton and Sandy Harris purchase buttons from John Jefferson as they wait to see U.S. Senator Bernie Sanders speaks at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA

Photo: Paul Kuroda, Special To The Chronicle

California and national nurses rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sen. Bernie Sanders, I-Vt., spoke at the National Nurses United rally to promote his Medicare for All 2017 plan. less

California and national nurses rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sen. Bernie Sanders, I-Vt., spoke at the National Nurses United rally to promote his Medicare for … more

Photo: Santiago Mejia, The Chronicle

National Nurses United executive director RoseAnn DeMoro during a rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sen. Bernie Sanders, I-Vt., spoke at the nurses rally to promote his Medicare for All 2017 plan. less

National Nurses United executive director RoseAnn DeMoro during a rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sen. Bernie Sanders, I-Vt., spoke at the nurses rally to … more

Photo: Santiago Mejia, The Chronicle

Sen. Bernie Sanders, I-Vt., during a nurses convention rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sanders promoted his Medicare for All 2017 plan.

Sen. Bernie Sanders, I-Vt., during a nurses convention rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sanders promoted his Medicare for All 2017 plan.

Photo: Santiago Mejia, The Chronicle

Sen. Bernie Sanders, I-Vt., during a California nurses convention rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sanders spoke to promote his Medicare for All 2017 plan.

Sen. Bernie Sanders, I-Vt., during a California nurses convention rally at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sanders spoke to promote his Medicare for All 2017 plan.

Photo: Santiago Mejia, The Chronicle

Sarah Johnson rallies with a California nurses convention at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sen. Bernie Sanders, I-Vt., spoke at the nurses rally to promote his Medicare for All 2017 plan. less

Sarah Johnson rallies with a California nurses convention at Yerba Buena Gardens on Friday, Sept. 22, 2017, in San Francisco, Calif. Sen. Bernie Sanders, I-Vt., spoke at the nurses rally to promote his Medicare … more

Photo: Santiago Mejia, The Chronicle

Delhi Donis, from Mexico gave U.S. Senator Bernie Sanders a rose and was brushed away by Campus Police officers at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA.

Delhi Donis, from Mexico gave U.S. Senator Bernie Sanders a rose and was brushed away by Campus Police officers at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA.

Photo: Paul Kuroda, Special To The Chronicle

Delhi Donis, from Mexico gives U.S. Senator Bernie Sanders a rose before he spoke to the overflow section at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA. She was brushed away by Campus Police for being too close. less

Delhi Donis, from Mexico gives U.S. Senator Bernie Sanders a rose before he spoke to the overflow section at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA. She was brushed away … more

Photo: Paul Kuroda, Special To The Chronicle

U.S. Senator Bernie Sanders speaks at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA

U.S. Senator Bernie Sanders speaks at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA

Photo: Paul Kuroda, Special To The Chronicle

Jessica Buchsbaum records the speech of U.S. Senator Bernie Sanders speaking at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA.

Jessica Buchsbaum records the speech of U.S. Senator Bernie Sanders speaking at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA.

Photo: Paul Kuroda, Special To The Chronicle

U.S. Senator Bernie Sanders speaks at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA

U.S. Senator Bernie Sanders speaks at City College of San Francisco on Friday, Sept. 22, 2017 in San Francisco, CA

Sen. Bernie Sanders barnstormed friendly progressive audiences Friday in San Francisco to build support for his Medicare-for-all proposal, saying it wasn’t enough just to play defense against “horrific” Republican health care plans.

“Maintaining the status quo is not enough,” Sanders said. “Our job is not just to prevent tens of millions of Americans from being thrown off the health insurance they currently have. Our job is to join every other major country on Earth and guarantee health care to all as a right, not a privilege.

“The time has come for a single-payer, Medicare-for-all program,” Sanders said at a downtown rally at Yerba Buena Gardens dominated by red-shirt wearing members of the California Nurses Association/National Nurses Organizing Committee, which was holding its convention at a hotel across the street. The 185,000-member union, which is headquartered in Oakland, was one of the earliest and most vocal supporters of the Vermont independent senator and, like him, is a longtime backer of single-payer health care.

Sanders did, however, praise one Republican — fellow Sen. John McCain — for having the “conscience” to oppose the latest GOP attempt to repeal Obamacare.

“John McCain has a conscience that I wish the rest of the Republican Party leadership had,” Sanders said. The former presidential candidate and America’s best-known progressive was referring to the announcement by McCain, R-Ariz., earlier in the day that he would not support the latest GOP health care bill, introduced by Sens. Lindsey Graham of South Carolina and Bill Cassidy of Louisiana and expected to be voted on next week.

Sanders was in San Francisco for a series of appearances to bolster support for the Medicare-for-all legislation he just introduced in the Senate. Sanders also appeared at a public rally at City College of San Francisco and at a private town hall event at Credo Action, a social activist network.

For Sanders, speaking to friendly liberal audiences was like political spring training before his scheduled debate Monday evening on CNN with Graham and Cassidy. Sen. Amy Klobuchar, D-Minn., who does not support Sanders’ proposal, will join him for the debate.

While single-payer health care was considered on the political fringe as recently as last year’s presidential campaign, Sanders’ bill quickly drew support from 15 of his Democratic Senate colleagues. They include several who appear on the short list of potential 2020 presidential candidates, including Sens. Kamala Harris of California, Elizabeth Warren of Massachusetts and New Jersey’s Cory Booker.

While the public is warming toward single payer, a survey this month from the nonpartisan Kaiser Family Foundation found that attitudes about it are “malleable.” Fifty-five percent of respondents said they support getting their health coverage from a single government plan, but that support dropped when they were told their taxes would likely go up.

Sanders’ 94-page bill, which is modeled on the single-payer health care found in other countries, calls for an overhaul of the nation’s health care system. It would transform the current hybrid system of private and public insurance into a single system administered by the federal government.

During a four-year phase-in, it would eliminate premiums, co-payments and deductibles, and cover vision and dental care.

It’s unclear how it would be funded, though Sanders has proposed a couple of ideas, including a 7.5 percent employer payroll tax, a 4 percent individual income tax and several levies on wealthier Americans.

“My Republican friends will tell you that you may have to pay more in taxes — and, depending on your income, that’s true,” Sanders said Friday. “But what they won’t tell you is that you’re no more going to have pay that five, 10, 20,000 dollars to the private insurance companies.”

He warned his supporters that if his bill advances, the insurance and pharmaceutical companies would fight back hard. He recalled how the pharmaceutical industry spent $111 million last year to defeat California’s Proposition 61, which would have regulated drug prices by requiring state agencies to pay no more than what the federal Department of Veterans Affairs pays for prescription medication.

If drug companies spend that much “in one state to defeat one referendum, think about what they’re going to be spending all across this country to defeat a Medicare-for-all proposal,” Sanders said.

Efforts in California to enact universal health care stalled in the Legislature, where Democratic leaders balked at estimates that it would cost $400 billion, nearly twice as much as the state’s annual budget, each year.

Speaking to the nurses convention earlier Friday, Lt. Gov. Gavin Newsom said he’ll fight for universal health coverage if he is elected governor next year.

“If we can’t get it done next year, you have my firm and absolute commitment as your next governor that I will lead the effort to get it done,” Newsom said to a standing ovation from the nurses, who have endorsed his candidacy. “We will get universal health care.”

At City College, Sanders praised the San Francisco Board of Supervisors, which in February announced the two-year Free City College pilot program to spend $5.4 million each year to pay the $46-a-credit fee usually paid by students. The money will come from a voter-approved tax on San Francisco properties that sell for at least $5 million and is expected to raise about $44 million a year for the city.

“You are becoming a model for the United States of America,” Sanders said. He predicted that “young people and working people and parents all over this country are asking their local officials, ‘Hey, how come in San Francisco they can make college tuition-free, why don’t you do that in our community?’”